sodium nitrite can be added to the test tube.... & 4 estimation, U GOT iRON KITS !! FROM MANY COMPANIES LIKE aCCUREX, BD , etc... more effective is an immuno- turbidimetric method.... also, Evelyn and Malloy method can be used for Metheamoglobin :-)

Thank you very much.

1.The classical method of analyzing MetHb is Evelyn-Malloy method. You could download the pdf file form JBC magazine. websites:Evelyn KA, Malloy HT. Microdetermination of oxyhemoglobin, methemoglobin, and sulfhemoglobin in a single sample of blood. J Biol Chem 1938;126:655-662.

2.On-line detection method is calculative by spectrophotometry. for exampla:Blood gas analysis instrument,Chiron 800 System or GEM OPL.(our labs are using GEM OPL.http://www.instrumentationlaboratory.com/benelux/products%20services/critical%20care%20diagnostics/instruments/gem%20opl.aspx).

1973 PNAS Pyridoxal Compounds as Specific Reagents for the α and β N-Termini of Hemoglobin.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC427063/

3.Other methods:isoabsorptive point method; NMR; Zero Field Split; Raman spectrum etc....

I hope these information could be helpful

adding ferricyanid to the hemoglobin solution you will get methemoglobin (solution: 0.2g K 3 Fe (CN) 6 and 1.0g NaHCO3 in 1 liter)

all commercial kit for iron determination in serum provide a reducing solution; try to make the assay before and after addition of the reducing solution

adding 10 drops of 10% k3 fe (cn)6 on the side of test tube.